Everyone used to build their own RCA's back in the late 80's. We did it just so the lengths would be right.
Funny, back then, RCA's started to look like water hoses...conductor, shielding, shielding for the shielding, 'drain' for the shielding, etc. Then, at finals one year, Richard Clark showed up with two rolls of 20 ga wire, and some ends. Twisted the wires together with a drill, soldered ends to them and wired up a system on a bench. Then, he threw all sorts of EMF at them...even wrapped them around a turning alternator...no noise, even on a scope. Someone then brought a 'high end' water hose looking cable, and ran the same test. This time, there was noise. It was small, but it was there. It was then that we all learned that the twisting rejects the noise.
So, for a bunch of years, RCA's got really thin, as the world realized that no additional shielding was necessary. Now, I'm starting to see fat wires, with all sorts of shielding, over top of the twisted pair, showing up again. I guess people think they are getting more.
So, as long as you can solder, and buy decent ends, you'll save money making your own, and you'll have exactly the lengths you need, every time. Dalton's idea of Cat5 makes great sense, but you could technically just twist some wires together, and get the same result.
All that being said, I don't make my own anymore...just don't feel like it.
Toby
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Toby Johnson
BlackDog Racing
BlackDog Speed Shop
Lincolnshire, IL